Effects of swine manure dilution with lagoon effluent on microbial communities and odor formation in pit recharge systems

Pit recharge systems (PRS) control odor by managing organic solids in swine manure. However, there needs to be more understanding of PRS's effect on the microbiome composition and its impact on odor formation. A study was conducted to understand how recharge intervals used in PRS impact manure microbiome and odor formation. Bioreactors dynamically loaded simulated recharge intervals of 14, 10, and 4 days by diluting swine manure with lagoon effluent at varying ratios. Treatment ratios tested included 10:0 (control), 7:3 (typical Korean PRS), 5:5 (enhanced PRS #1), and 2:8 (enhanced PRS #2). Manure microbial membership, chemical concentrations, and odorant concentrations were used to identify the interactions between microbiota, manure, and odor. The initial microbial community structure was controlled by dilution ratio and manure barn source material. Firmicutes and Proteobacteria were the dominant microbial phyla in manure and lagoon effluent, respectively, and significantly decreased or increased with dilution. Key microbial species were Clostridium saudiense in manure and Pseudomonas caeni in lagoon effluent. Percentages of these species declined by 8.9% or increased by 17.6%, respectively, with each unit dilution. Microbial community composition was controlled by both treatment (i.e., manure dilution ratio and barn source material) and environmental factors (i.e., solids and pH). Microbiome composition was correlated with manure odor formation profiles, but this effect was inseparable from environmental factors, which explained over 75% of the variance in odor profiles. Consequently, monitoring solids and pH in recharge waters will significantly impact odor control in PRS.

Evaluation of Actual Ventilation Rates and Efficiency in Research-Scale Pig Houses Based on Ventilation Configurations

Accurate ventilation control is crucial for maintaining a healthy and productive environment in research-specialized pig facilities. This study aimed to evaluate actual ventilation rates and ventilation efficiency by investigating different inlet and exhaust configurations. The research was conducted in two pig rooms, namely pig room A and pig room B, in the absence of animals and workers to focus solely on evaluating the ventilation system's performance. Actual ventilation rates were measured using hood-type anemometers, and the local air change per hour was analyzed at various measurement points via tracer gas decay experiments. The results demonstrated that specific inlet and exhaust combinations, such as side inlet/chimney outlet and ceiling inlet/side outlet, exhibited higher ventilation rates. However, the measured ventilation rates were much lower than the manufacturer's specifications. The side exhaust fan closer to the pig activity space demonstrated better ventilation effectiveness for the animals than the chimney exhaust fan. Additionally, the ceiling inlet exhibited superior air distribution and uniformity. Lower ventilation rates and higher infiltration ratios resulted in reduced ventilation efficiency, with the difference between pig and worker activity spaces being pronounced. This study emphasizes the importance of selecting optimal inlet and exhaust configurations to achieve efficient ventilation and create a healthy environment for both pigs and workers.

Impact of Bacillus subtilis on manure solids, odor, and microbiome

A study was conducted to determine the effectiveness of supplementing swine manure with Bacillus subtilis (BS) to improve digestion of manure solids and lower odor emission. Large bioreactors (400 L) with manure (100 L) were treated with commercially available BS at a rate of 1% manure volume by either directly pouring or surface spraying the manure with inoculum. Manure physicochemical properties, gas emissions, and microbiome were monitored. Manures treated multiple times with BS or surface sprayed had significantly (P < 0.05) lower electrical conductivity, volatile solids, and chemical oxygen demand, by 3-5% compared to non-treated control manures. Volatile sulfur compound emissions (VSCs) were reduced by 20-30% in both experiments, while ammonia and volatile organic compounds were reduced by 40% and 15%, respectively, in surface spray experiment only. The manure indigenous microbiome remained relatively stable following treatment and BS were never detected in the raw or treated manure following multiple treatments. The reduction in manure organic carbon and VSCs emissions were a result of physical mixing during manure treatment and biological material in the microbial inoculum stimulating microbial activity and not growth of BS.

Comprehensive analysis of microbial dynamics linked with the reduction of odorous compounds in a full-scale swine manure pit recharge system with recirculation of aerobically treated liquid fertilizer

It is believed that the generation of odorous materials in manure-slurry pits during the storage can be reduced by recirculating aerobically treated liquid fertilizer (ATLF) to a manure-pit recharge system (PRS). However, the biological mechanisms for reduction of those problematic compounds remain poorly understood. In this study, the links between microbial evolution and changes in chemical composition and odorous compounds were analyzed where swine-manure slurry was stored in a full-scale PRS. Some beneficial microorganisms were successfully established in the PRS. This resulted in the accumulation of fewer undesirable chemical components and lower amounts of odorous compounds compared to those in a conventional swine-manure slurry pit (the control). Decrease in the volatile fatty acids (1387-8478 mg/L → 306-1258 mg/L) and NH₃ (3387-4300 mg/L → 85-200 mg/L) in the PRS was mainly due to the development of a key community that included a mix of aerobic, anaerobic fermentative, nitrifying (0.1-0.6%) and denitrifying (1.7-3.5%), and methanogenic microorganisms (2.1-4.2%). Meanwhile, the generation of greater amounts of H₂S (12-290 mg/L → 61-1754 mg/L) was found in the PRS, which condition was supported by the increased proportion of sulfate-reducing bacteria (0.5-3%). To the authors' best knowledge this is the first study comprehensively analyzing microbial dynamics linked with the reduction of odorous compounds in the full-scale PRS in response to recirculation of ATLF.

Meta-analysis identifies the effect of dietary multi-enzyme supplementation on gut health of pigs

Gut health though is not well defined the role of gastrointestinal tract is vital if an animal must perform well. Apart from digestion, secretion, and absorption gut is harbored with consortium of microbiota which plays a key role in one's health. Enzymes, one of the alternatives for antibiotics with beneficial effects on digestion and consistency of food and its effect on gut health. The effect of enzyme supplementation on gut health is not well established and the objective of this meta-analysis is to investigate if the enzyme supplement has influence on gut. This meta-analysis includes 1221 experiments which has single enzyme studies and or studies with multiple enzyme complexes but not challenged. The ratio of Lactobacillus and E. coli is related to ADFI which showed comparatively lower negative correlation coefficient, with - 0.052 and - 0.035, respectively, whose I2 values are below 25%, showing that these studies show a significantly lower level of heterogeneity. Correlation between villus height, crypt depth, their ratio and fatty acid is also assessed, and it showed that when the animal is supplemented with two enzyme complexes resulted in positive gut health rather than the single or more than two enzymes.

Swine manure dilution with lagoon effluent impact on odor reduction and manure digestion

Manure management systems have a major impact on odor from swine operations. A study was conducted to compare deep-pit manure management systems to flushing barn manure management systems for odor reduction and organic matter degradation. Bioreactors were used to mimic manure management systems in which manure and lagoon effluent were loaded initially, and subsequent manure was added daily at 5% of its storage capacity (1 L). Final manure-to-lagoon effluent ratios were 10:0 (deep-pit manure management system), 7:3 (Korean flushing systems), 5:5 (enhanced flushing systems), and 2:8 (enhanced flushing systems). At the end of the trial, at 4 (2:8), 10 (5:5), or 14 (10:0, 7:3) d, manure and gas concentrations of odorants were measured, including total solids (TS), total N (TN), and total C (TC) of manure. Odor was evaluated using the odor activity values (OAVs), and regression analysis was used to determine the effects of dilution and TS on manure properties and OAVs. Solids in the manure were positively correlated to TN, TC, straight chain fatty acids (SCFAs), branch chain fatty acids (BCFAs), total phenols, and total indoles and positively correlated to OAV for SCFAs, BCFAs, ammonia, total phenols, and total indoles. Reducing TS by 90% reduced BCFA, ammonia, phenols, and indoles by equal amounts in air. Carbon dioxide was the main C source evolved, averaging over 90%, and CH₄ increased with dilution quadratically. Overall, reducing solids in manure by dilution had the biggest impact on reducing odor and increasing organic C degradation.

OP0233 EFFICACY, SAFETY, AND PHARMACODYNAMIC EFFECTS OF THE BRUTON’S TYROSINE KINASE INHIBITOR, FENEBRUTINIB (GDC-0853), IN MODERATE TO SEVERE SYSTEMIC LUPUS ERYTHEMATOSUS IN A PHASE 2 CONTROLLED STUDY

Background:

Fenebrutinib (GDC-0853, FEN) is an oral, non-covalent, and selective inhibitor of Bruton’s tyrosine kinase (BTK) in clinical development for autoimmune diseases.

Objectives:

This was a randomized, placebo-controlled, multi-center study to evaluate the efficacy, safety, and pharmacodynamic effects of FEN in patients with moderate-to-severe systemic lupus erythematosus (SLE) activity.

Methods:

Patients who met SLICC or revised ACR SLE criteria, had ≥1 serologic marker of SLE, SLEDAI ≥8, and were on ≥1 standard of care (SOC) therapy were included; patients with renal or CNS involvement, or exposure to B cell depleting or calcineurin inhibitor therapy were excluded. Patients were randomized to placebo (PBO), FEN 150 mg QD, or FEN 200 mg BID, for 48 weeks. A corticosteroid taper was recommended, with burst and taper permitted from Week 0 (W0) to W12 and W24 to W36. The primary endpoint was SRI-4 at W48. Post hoc subgroup analyses were conducted based on patient baseline disease characteristics.

Results:

This study enrolled 260 patients, with the majority recruited in Latin America, USA, and Western Europe. At W48, the SRI-4 response rates for FEN 150 mg QD and FEN 200 mg BID were 51% (95% CI: -8.5, 21.2; p value 0.37) and 52% (95% CI: -7.3, 22.4; p value 0.34), respectively, compared to 44% for PBO (Table 1). Post-hoc analysis showed larger responses in subgroups of patients with higher baseline disease activity (Table 1). Safety results were similar between FEN and PBO arms, although more serious adverse events were observed in the FEN 200 mg BID arm. Study discontinuations were balanced across the 3 arms (24-26%). FEN treatment significantly reduced levels of CD19+ B cells, anti-dsDNA autoantibodies, IgG, and a BTK-dependent RNA signature highly expressed in plasmablasts by W48 compared to PBO; C4 levels modestly improved with FEN vs. PBO (Table 2).

Table 1.

SRI-4 Response (%) at W48 in Primary Analysis and in Post-hoc Patient Subgroups

PBOFEN 150 mg QDFEN 200 mg BIDSRI-4 Response (%) at W4844n=8451n=8752n=88SRI-4 Response (%) in Baseline Subgroups At least 1 BILAG A48n=4254n=3959n=46 At least 1 BILAG A and SLEDAI increased DNA binding37n=1953n=1765n=26 SLEDAI arthritis with at least 4 swollen joints39n=5750n=5457n=54 SLEDAI arthritis with at least 4 tender joints39n=7153n=7059n=69 CLASI >=1021n=1436n=1131n=16Table 2.

Key Biomarker Results

PBOFEN 150 mg QDFEN 200 mg BIDMedian (%) Change from Baseline at W48 Plasmablast signature-19.7%n=52-54.3%*n=53-51.7%*n=57 CD19+B cells (cells/µl)-0.50n=38-57.0*n=49-57.5*n=48 Anti-dsDNA#(IU/ml)+6.9n=31-38.3*n=36-75.7*n=33 Total IgG (g/L)-0.20n=65-1.25*n=64-1.56*n=64 C3 (g/L)-0.02n=65+0.01n=67-0.01n=66 C4 (g/L)0.00n=65+0.02*n=67+0.01*n=66

#Patients who were positive at baseline (>30 IU/mL)

*Denotes significant vs. PBO; Kruskal-Wallis false-discovery rate controlled two sided (p-value ≤0.05)

Conclusion:

The primary endpoint of SRI-4 for FEN was not met despite evidence of strong BTK target and pathway inhibition. FEN had an acceptable safety profile. Several disease activity subgroups were suggestive of a greater treatment effect on SRI-4 compared to PBO

Disclosure of Interests:

David Isenberg Consultant of: Study Investigator and Consultant to Genentech, Richard Furie Grant/research support from: AstraZeneca, Biogen, Consultant of: AstraZeneca, Biogen, Nicholas S. Jones Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Pascal Guibord Shareholder of: Roche, Employee of: Roche, Joshua Galanter Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Chin Lee Shareholder of: Genentech/Roche and Eli Lilly, Employee of: Genentech/Roche, Anna McGregor Employee of: Genentech/Roche, Balazs Toth Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Julie Rae Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Olivia Hwang Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Armend Lokku Shareholder of: Roche, Employee of: Roche, Pedro Miranda Consultant of: Study Investigator for Genentech, Viviane de Souza Consultant of: Study investigator for Genentech, Juan Jaller-Raad Consultant of: Study investigator for Genentech, Anna Maura Fernandes Consultant of: Study investigator for Genentech, Rodrigo Garcia Salinas Consultant of: Study investigator for Genentech, Leslie Chinn Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Michael J. Townsend Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Alyssa Morimoto Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Katie Tuckwell Shareholder of: Genentech/Roche, Employee of: Genentech/Roche

Effects of amino acid composition in pig diet on odorous compounds and microbial characteristics of swine excreta

Background

Major amino acids in pig diets are Lys, Met, Thr, and Trp, but little is known about the requirements for the other essential amino acids, especially on odorous compounds and microbial characteristics in feces of growing-finishing pigs. To this end, different levels of amino acid composition added to diets to investigate the effects of amino acid composition on microbial characteristics and odorous compounds concentration.

Methods

A total eight (n = 8) barrows (Landrace × Yorkshire × Duroc) with an average bodyweight of 89.38 ± 3.3 kg were individually fed diets formulated by Korean Feeding Standards 2007 (old version) or 2012 (updated with ideal protein concept) in metabolism crates with two replication. After 15-day adaptation period, fresh faecal samples were collected directly from pigs every week for 4 weeks and analysed for total volatile fatty acids (VFA), phenols and indoles by using gas chromatography. The nitrogen was determined by Kjeldahl method. Bacterial communities were detected by using a 454 FLX titanium pyrosequencing system.

Results

Level of VFA tended to be greater in 2012 than 2007 group. Among VFAs, 2012 group had greater (p < 0.05) level of short chain fatty acids (SCFA) than control.Concentration of odorous compounds in feces was also affected by amino acid composition in pig diet. Levels of ammonium and indoles tended to be higher in 2012 group when compared with 2007 group.Concentration of phenols, p-cresol, biochemical oxygen demand, and total Kjeldahl nitrogen, however, were lower (P < 0.05) in 2012 treatment group compare to 2007. The proportion of Firmicute phylum were decreased, while the Bacteriodetes phylum proportion increased and bacterial genera includingCoprococcus, Bacillus, and Bacteroides increased (p < 0.05) in 2012 compare to 2007 group.

Conclusion

Results from our current study indicates that well balanced amino acid composition reduces odor by modulating the gut microbial community. Administration of pig diet formulated with the ideal protein concept may help improve gut fermentation as well as reduce the odor causing compounds in pig manure.

Effect of Dietary Protein Levels on Composition of Odorous Compounds and Bacterial Ecology in Pig Manure

This study was performed to investigate the effect of different levels of dietary crude protein (CP) on composition of odorous compounds and bacterial communities in pig manure. A total of 48 male pigs (average initial body weight 45 kg) fed diets containing three levels of dietary CP (20%, 17.5%, and 15%) and their slurry samples were collected from the pits under the floor every week for one month. Changes in composition of odorous compounds and bacterial communities were analyzed by gas chromatography and 454 FLX titanium pyrosequencing systems, respectively. Levels of phenols, indoles, short chain fatty acid and branched chain fatty acid were lowest (p<0.05) in CP 15% group among three CP levels. Relative abundance of Bacteroidetes phylum and bacterial genera including Leuconostoc, Bacillus, Atopostipes, Peptonphilus, Ruminococcaceae_uc, Bacteroides, and Pseudomonas was lower (p<0.05) in CP 15% than in CP 20% group. There was a positive correlation (p<0.05) between odorous compounds and bacterial genera: phenol, indole, iso-butyric acid, and iso-valeric acid with Atopostipes, p-cresol and skatole with Bacteroides, acetic acid and butyric acid with AM982595_g of Porphyromonadaceae family, and propionic acid with Tissierella. Taken together, administration of 15% CP showed less production of odorous compounds than 20% CP group and this result might be associated with the changes in bacterial communities especially whose roles in protein metabolism.

A humanized monoclonal antibody targeting the β7 integrin selectively blocks intestinal homing of T lymphocytes

BACKGROUND AND PURPOSE

rhuMAb Beta7 is a humanized anti-human β7 monoclonal antibody currently in phase I in inflammatory bowel disease. rhuMAb Beta7 binds the β7 subunit of the integrins α4β7 and αEβ7, blocking interaction with their ligands. These integrins play key roles in immune cell homing to and retention in mucosal sites, and are associated with chronic inflammatory diseases of the gastrointestinal tract. The goal of this study was to evaluate the mucosal specificity of rhuMAb Beta7.

EXPERIMENTAL APPROACH

We assessed the effect of murine anti-Beta7 on lymphocyte homing in mouse models of autoimmune disease. We also compared the effect of rhuMAb Beta7 on circulating mucosal-homing versus peripheral-homing T cells in naïve non-human primates.

KEY RESULTS

In cynomolgus monkeys, occupancy of β7 integrin receptors by rhuMAb Beta7 correlated with an increase in circulating β7(+) mucosal-homing lymphocytes, with no apparent effect on levels of circulating β7(-) peripheral-homing lymphocytes. rhuMAb Beta7 also inhibited lymphocyte homing to the inflamed colons of severe combined immunodeficient mice in CD45RB(high) CD4(+) T-cell transfer models. Consistent with a lack of effect on peripheral homing, in a mouse model of experimental autoimmune encephalomyelitis, anti-β7 treatment resulted in no amelioration of CNS inflammation.

CONCLUSIONS AND IMPLICATIONS

The results presented here suggest that rhuMAb Beta7 selectively blocks lymphocyte homing to the gastrointestinal tract without affecting lymphocyte trafficking to non-mucosal tissues. rhuMAb Beta7 provides a targeted therapeutic approach with the potential for a more attractive benefit:risk ratio than currently available inflammatory bowel disease therapies.

B-cell subsets in blood and lymphoid organs in Macaca fascicularis

BACKGROUND

Cynomolgus monkeys (Macaca fascicularis) are widely used animal models in biomedical research. However, the phenotypic characteristics of cynomolgus monkey (CM) B cells in peripheral blood (PB) and lymphoid organs are poorly understood.

METHODS

FACS analyses of PB-, spleen-, lymph node (LN)-, and bone marrow (BM)-derived B cells were performed.

RESULTS

CM peripheral blood B cells have a smaller fraction of CD27(-) (naive) cells ( approximately 40%), as compared to human blood samples ( approximately 70%). Similar to humans, an early activation marker, CD23, is expressed more on CD27(-) CM naive B cells, as compared to CD27(+) B cells. The mean fraction of B cells exhibiting a memory phenotype is similar to that seen in human blood. Unlike humans, CM blood contains a subset of CD20(++)CD80(+)CD21(-)IgM(+/-)CD27(+)CD19(+)FSC(++)BAFF-R(low) B cells that are likely of germinal center origin. Thus, CM blood contains (i) a higher percentage of B cells that express the co-stimulatory molecule CD80, and (ii) a lower fraction of B cells that are CD21(+), as compared to human blood. Due to the relative paucity of information on B-cell subsets in organs of healthy humans, a direct comparison between human and CM lymphoid organ data is limited. The fraction of CD27(+) and CD23(+) B cells appears to be similar, while the fraction of CD80(+) B cells appears to be higher than that seen in human lymphoid organs. CM spleens and to some extent lymph nodes have a distinct subset of CD21(++) cells that are also CD80(+/-)CD23(low)IgM(++)CD27(+/-)FSC(++). This subset is phenotypically similar to the marginal zone B cells present in human spleen and LN samples. We also provide detailed analyses on the fraction of lymphoid organ B cells that express CD21, CD23, CD32, and/or CD80 B-cell markers.

CONCLUSIONS

In general, cynomolgus monkey B-cell subsets are similar to those seen in humans, as well as to those seen in other nonhuman primates. However, there are some clear differences between human and cynomolgus monkey B-cell subsets. These findings have direct implications for a variety of in vivo studies in cynomolgus monkeys, ranging from basic research on primate B-cell differentiation to models of infectious diseases and trials of new B-cell targeting therapeutic agents.

Synthetic phytoceramides induce apoptosis with higher potency than ceramides

Ceramides are naturally occurring compounds recognized to mediate apoptosis. N-acylsphingosines, containing a double bond at carbons 4 and 5 of their sphingoid backbone, are thought to be the active form, because N-acylsphinganines with completely saturated sphingoid are inactive. In the present study, we synthesized a series of N-acyl-4D-ribo-phytosphingosines (phytoceramides) that contain a hydroxyl group at carbon 4 and investigated structure-cytotoxicity relationship of the presumed functional groups in ceramides. N-Acetylphytoceramide (PCer2) and N-hexanoylphytoceramide (PCer6) were found to be more cytotoxic than ceramides as determined by released lactate dehydrogenase activity and morphological criteria. This was not caused by intracellular conversion of phytoceramides to ceramides, because no N-hexanoylsphingosine was formed after incubation of cell lysate with PCer6. Among phytoceramides having acyl chains two to eight carbons long, the cytotoxicity was highest with five or six carbons. The carbonyl group of the amide bond did not seem to be critical, because substitution of the oxygen with sulfur did not influence the cytotoxicity. The phytoceramide-induced cell death was observed to be apoptotic in nature with the use of terminal deoxynucleotidyl transferase dUTP nick-end labeling and propidium iodide staining. Because phytoceramides can be readily synthesized from yeast sources, they may present a potential and economical alternative to ceramide in future studies and therapies.

Down-regulation of GTP cyclohydrolase I and tetrahydrobiopterin by melatonin

Tetrahydrobiopterin (BH4) is spontaneously released and extracellularly exerts a toxic effect preferentially on catecholamine cells. Its synthesis rate is mainly determined by the activity of the enzyme GTP cyclohydrolase I (GTPCH). In the present study, role of melatonin BH4 synthesis was determined using the catecholaminergic CATH.a cells. The neurohormone dose-dependently reduced both intracellular and extracellular BH4 levels. This was due to both direct inhibition of catalytic activity of the existing GTPCH enzyme and down-regulation of GTPCH gene expression. Thus, melatonin is an effective down-regulator of BH4 synthesis and is a potential therapeutic agent with which to control BH4 level in aberrant conditions where it may rise to a toxic level.

Tetrahydrobiopterin is released from and causes preferential death of catecholaminergic cells by oxidative stress

The underlying cause of the selective death of the nigral dopaminergic neurons in Parkinson's disease is not fully understood. Tetrahydrobiopterin (BH4) is synthesized exclusively in the monoaminergic, including dopaminergic, cells and serves as an endogenous and obligatory cofactor for syntheses of dopamine and nitric oxide. Because BH4 contributes to the syntheses of these two potential oxidative stressors and also undergoes autoxidation, thereby producing reactive oxygen species, it was possible that BH4 may play a role in the selective vulnerability of dopaminergic cells. BH4 given extracellularly was cytotoxic to catecholamine cells CATH. a, SK-N-BE(2)C, and PC12, but not to noncatecholamine cells RBL-2H3, CCL-64, UMR-106-01, or TGW-nu-1. This was not caused by increased dopamine or nitric oxide, because inhibition of their syntheses did not attenuate the damage and BH4 did not raise their cellular levels. Dihydrobiopterin and biopterin were not toxic, indicating that the fully reduced form is responsible. The toxicity was caused by generation of reactive oxygen species, because catalase, superoxide dismutase, and peroxidase protected the cells from the BH4-induced demise. Furthermore, thiol agents, such as reduced glutathione, dithiothreitol, beta-mercaptoethanol, and N-acetylcysteine were highly protective. The BH4 toxicity was initiated extracellularly, because elevation of intracellular BH4 by sepiapterin did not result in cell damage. BH4 was spontaneously released from the cells of its synthesis to a large extent, and the release was not further enhanced by calcium influx. This BH4-induced cytotoxicity may represent a mechanism by which selective degeneration of dopaminergic terminals and neurons occur.

TGF-beta(1) down-regulates inflammatory cytokine-induced VCAM-1 expression in cultured human glomerular endothelial cells

BACKGROUND

Endothelial cells are active participants in the processes controlling coagulation, inflammation and the immune response. Variations are recognized between endothelia isolated from different vascular beds as well as from different species. Though transforming growth factor-beta(1) (TGF-beta(1)) has been known to have an anti-inflammatory action, little is known about its effect on expression of cellular adhesion molecules during the inflammatory process in human glomerular endothelial cells. The aim of this study was to determine the effect of TGF-beta(1) on the inflammatory cytokine-induced expression of vascular cell adhesion molecule-1 (VCAM-1) in cultured human glomerular endothelial cells.

METHODS

The culture of human glomerular endothelial cells was established using the normal portion of nephrectomized renal tissues and identified by factor VIII staining and cellular uptake of fluorescent-labelled acetylated low-density lipoprotein (LDL). The endothelial cells were stimulated by interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) with or without TGF-beta(1). Cellular expression of VCAM-1 was measured by enzyme-linked immunosorbent assay (ELISA) and flow cytometry, and VCAM-1 mRNA was measured by Northern blot analysis.

RESULTS

TGF-beta(1) (1, 10 and 25 ng/ml) blunted IL-1beta- (5 ng/ml) induced VCAM-1 expression significantly (OD=1.08+/-0.14, 1. 10+/-1.16 and 1.05+/-0.14 vs IL-1beta=1.97+/-0.29, n=6, P<0.05) in ELISA. The addition of TGF-beta(1) (1, 10 and 25 ng/ml) also suppressed TNF-alpha- (10 ng/ml) induced VCAM-1 expression (OD=1. 14+/-0.15, 1.17+/-0.17 and 1.18+/-0.16 vs TNF-alpha=1.96+/-0.26, n=6, P<0.05). The same results were obtained by flow cytometry. TGF-beta(1) (10 ng/ml) inhibited both IL-1beta- (5 ng/ml) and TNF-alpha-(10 ng/ml) induced expression of VCAM-1 (MFI: IL-1beta=90. 8+/- 17.6, IL-1beta+TGF-beta(1)=37.8+/-14.9, TNF-alpha=113.6+/- 12.4, TNF-alpha+TGF-beta(1)=64.3+/-13.8, mean+/-SD, n=3, P<0.05). By Northern blot analysis, TGF-beta(1) (10 ng/ml) significantly suppressed the stimulatory effect of IL-1beta and TNF-alpha.

CONCLUSIONS

These results show that TGF-beta(1) down-regulates the inflammatory cytokine-induced expression of VCAM-1 in human glomerular endothelial cells, which could be a novel mechanism for the anti-inflammatory action of TGF-beta(1) during the inflammatory processes in human glomerular diseases.

Up-regulation of GTP cyclohydrolase I and tetrahydrobiopterin by calcium influx

GTP cyclohydrolase I (GTPCH) catalyzes the first and rate-limiting reaction in the synthesis of tetrahydrobiopterin (BH4), an obligatory co-factor for monoamines and nitric oxide syntheses. Roles of calcium influx on transcript, protein and activity levels of GTPCH and BH4 availability were studied using primary cultured bovine adrenal medullary cells. Bovine GTPCH cDNA was isolated and used in Northern blot analyses. Ionomycin, A23187 and BayK8644 dramatically up-regulated GTPCH mRNA level. Depolarization by potassium or veratridine also induced GTPCH expression, which was abolished by EGTA. A23187 elevated GTPCH protein level, enzyme activity, and BH4 levels. Thus, calcium influx up-regulates GTPCH gene expression and BH4 levels which may contribute to neurotoxicity directly and/or via elevation of dopamine and nitric oxide.

Altered presynaptic gene expression in transgenic mice producing dopamine in the pineal gland

Neurotransmitters are known to play an important role in the development of the nervous system. We recently generated transgenic mice that ectopically express tyrosine hydroxylase (TH) and thereby produce dopamine (DA) de novo in pinealocytes of the pineal gland (PG). The transgenic PG also exhibited a dramatic decrease in TH-immunoreactive (IR) fibers putatively arising from the superior cervical ganglion (SCG) (Cho et al. [1996] Proc Natl Acad Sci USA 93:2862-2866). In the current study, however, we found that there was no reduction in the number of fibers immunostained for neurofilament protein or PGP9.5, markers known to be heavily localized in fibers, despite the reduction of TH fiber density. Therefore, we investigated whether the decreased TH-IR fiber density is the consequence of reduced sympathetic innervation, or a decrease in TH expression within innervating fibers. Immunohistochemical analysis comparing control and transgenic PG demonstrated no apparent differences in numbers of NPY- and aromatic-L-amino acid decarboxylase (AADC)-IR fibers, indicating that TH expression is decreased in a normal number of innervating fibers. Furthermore, presynaptic neurons in the transgenic SCG showed abnormal and heterogeneous TH immunoreactivity and reduced TH and norepinephrine transporter (NET) mRNA levels. These results show that ectopic DA production in the PG lowers TH and NET gene expression in the SCG without altering sympathetic innervation to the PG and suggest that the alteration of target neurotransmitter phenotype may influence gene expression of phenotype-specific proteins in projecting neurons.

Regulation of basal expression of catecholamine-synthesizing enzyme genes by PACAP

We have previously reported that the cAMP/protein kinase A (PKA) pathway is important in the gene regulation of both induction and basal expressions of the catecholamine synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). The neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) has been shown to activate the intracellular cAMP/PKA pathway. In the present study, using primary cultured bovine adrenal medullary cells, we determined whether the basal activity of the PACAP receptor might play a role in the maintenance of the basal expression of these enzyme genes via the cAMP/PKA pathway. The potent PACAP receptor antagonist PACAP (6-38) caused a reduction of TH and DBH mRNA levels in a dose dependent manner as well as their enzyme activities and TH protein level. The effects of PACAP (6-38) and the PKA inhibitor H-89 exhibited generally similar trends, and were not additive in the reduction of TH and DBH gene expression and activities, suggesting that they take a common intracellular signaling pathway. The antagonist also caused decreases in the intracellular norepinephrine and epinephrine levels similar to the effect of H-89. Taken together, the data suggests that PACAP is involved in the regulation of maintenance of the catecholamine synthesizing enzymes TH and DBH by utilizing the cAMP/PKA pathway.

Blockade of tetrahydrobiopterin synthesis protects neurons after transient forebrain ischemia in rat: a novel role for the cofactor

The generation of nitric oxide (NO) aggravates neuronal injury. (6R)-5,6,7,8-Tetrahydro-L-biopterin (BH4) is an essential cofactor in the synthesis of NO by nitric oxide synthase (NOS). We attempted to attenuate neuron degeneration by blocking the synthesis of the cofactor BH4 using N-acetyl-3-O-methyldopamine (NAMDA). In vitro data demonstrate that NAMDA inhibited GTP cyclohydrolase I, the rate-limiting enzyme for BH4 biosynthesis, and reduced nitrite accumulation, an oxidative metabolite of NO, without directly inhibiting NOS activity. Animals exposed to transient forebrain ischemia and treated with NAMDA demonstrated marked reductions in ischemia-induced BH4 levels, NADPH-diaphorase activity, and caspase-3 gene expression in the CA1 hippocampus. Moreover, delayed neuronal injury in the CA1 hippocampal region was significantly attenuated by NAMDA. For the first time, these data demonstrate that a cofactor, BH4, plays a significant role in the generation of ischemic neuronal death, and that blockade of BH4 biosynthesis may provide novel strategies for neuroprotection.

Differential involvement of PKA and PKC in regulation of catecholamine enzyme genes by PACAP

Roles of protein kinase A (PKA) and protein kinase C (PKC) in regulation of tyrosine hydroxylase, dopamine beta-hydroxylase, and phenylethanolamine N-methyltransferase expression by pituitary adenylate cyclase-activating polypeptide (PACAP) were determined in primary cultured bovine chromaffin cells. DBH up-regulation by PACAP was reduced by H-89 and not further increased by forskolin showing involvement of cAMP/PKA. It was not mediated by PKC, as 12-O-tetradecanoylphorbol-13-acetate and sphingosine exerted no effect. Tyrosine hydroxylase induction by PACAP was mediated by both kinases. The PACAP-activated PKA up-regulated phenylethanolamine N-methyltransferase expression whereas PKC caused down-regulation. PACAP increased tyrosine hydroxylase and dopamine beta-hydroxylase activities, but slightly lowered phenylethanolamine N-methyltransferase activity, resulting in a preferential rise in norepinephrine over epinephrine.

Inhibition of FGF-1 receptor tyrosine kinase activity by PD 161570, a new protein-tyrosine kinase inhibitor

Through direct synthetic efforts we discovered a small molecule which is a 40 nanomolar inhibitor of the human FGF-1 receptor tyrosine kinase. 1-Tert-butyl-3-[6-(2,6-dichloro-phenyl)-2-(4-diethylamino-butylamino)-py rido[2,3-d]pyrimidin-7-yl]-urea (PD 161570) had about 5- and 100-fold greater selectivity toward the FGF-1 receptor (IC50 = 40 nM) compared with the PDGFbeta receptor (IC50 = 262 nM) or EGF receptor (IC50 = 3.7 microM) tyrosine kinases, respectively. In addition, PD 161570 suppressed constitutive phosphorylation of the FGF-1 receptor in both human ovarian carcinoma cells (A121(p)) and Sf9 insect cells overexpressing the human FGF-1 receptor and blocked the growth of A121(p) cells in culture. The results demonstrate a novel synthetic inhibitor with nanomolar potency and specificity towards the FGF-1 receptor tyrosine kinase.

Localization of GTP cyclohydrolase in monoaminergic but not nitric oxide-producing cells

The first and rate-limiting enzyme in tetrahydrobiopterin (BH4) biosynthesis is GTP cyclohydrolase (GTPCH). BH4 serves as the essential cofactor for aromatic L-amino acid hydroxylases, such as tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), as well as for nitric oxide synthase (NOS). We hypothesized that to provide access to the cofactor, a close association exists between BH4-synthesizing and BH4-dependent enzymes, and we determined the relationship among GTPCH, neuronal NOS (nNOS), and TH in rat brain and adrenal gland using immunohistochemistry and in situ hybridization. Analyses of adjacent sections revealed specific localization of GTPCH in TH-containing cells of the substantia nigra, ventral tegmental area, hypothalamus, locus ceruleus, and adrenal medulla, and also in TPH-containing cells of the dorsal raphe nucleus and pineal gland. Thus, BH4 can be synthesized in all monoaminergic cells and is readily available for the enzymes requiring it. In contrast, analysis of adjacent sections showed that nNOS was not colocalized with GTPCH. Scattered nNOS-positive cells were found in the cortex, striatum, cerebellum, and olfactory bulb, all areas that receive monoaminergic innervation. The absence of GTPCH in nNOS cells suggests that nitric oxide-producing cells may either obtain biopterin from monoamine-containing processes which terminate in close proximity, or take up biopterin released into the blood. Double labelling of the same section for TH and nNOS revealed the TH nerve terminals connecting with the nNOS-positive cell bodies, suggesting the possibility that the BH4-containing nerve terminals may directly donate this cofactor to the nNOS-containing cells.

Isolation and characterization of Rhodobacter capsulatus mutants affected in cytochrome cbb3 oxidase activity

The facultative phototrophic bacterium Rhodobacter capsulatus contains only one form of cytochrome (cyt) c oxidase, which has recently been identified as a cbb3-type cyt c oxidase. This is unlike other related species, such as Rhodobacter sphaeroides and Paracoccus denitrificans, which contain an additional mitochondrial-like aa3-type cyt c oxidase. An extensive search for mutants affected in cyt c oxidase activity in R. capsulatus led to the isolation of at least five classes of mutants. Plasmids complementing them to a wild-type phenotype were obtained for all but one of these classes from a chromosomal DNA library. The first class of mutants contained mutations within the structural genes (ccoNOQP) of the cyt cbb3 oxidase. Sequence analysis of these mutants and of the plasmids complementing them revealed that ccoNOQP in R. capsulatus is not flanked by the oxygen response regulator fnr, which is located upstream of these genes in other species. Genetic and biochemical characterizations of mutants belonging to this group indicated that the subunits CcoN, CcoO, and CcoP are required for the presence of an active cyt cbb3 oxidase, and unlike in Bradyrhizobium japonicum, no active CcoN-CcoO subcomplex was found in R. capsulatus. In addition, mutagenesis experiments indicated that the highly conserved open reading frame 277 located adjacent to ccoNOQP is required neither for cyt cbb3 oxidase activity or assembly nor for respiratory or photosynthetic energy transduction in R. capsulatus. The remaining cyt c oxidase-minus mutants mapped outside of ccoNOQP and formed four additional groups. In one of these groups, a fully assembled but inactive cyt cbb3 oxidase was found, while another group had only extremely small amounts of it. The next group was characterized by a pleiotropic effect on all membrane-bound c-type cytochromes, and the remaining mutants not complemented by the plasmids complementing the first four groups formed at least one additional group affecting the biogenesis of the cyt cbb3 oxidase of R. capsulatus.

Protein kinase A coordinately regulates both basal expression and cyclic AMP-mediated induction of three catecholamine-synthesizing enzyme genes

Studies have shown that the cyclic AMP-regulated pathway is involved in the activation of tyrosine hydroxylase (TH) and in the induction of gene expression of the three catecholamine-synthesizing enzymes, TH, dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT). In the present study we investigated further the role of protein kinase A (PKA) in the regulation of both basal and cyclic AMP-inducible transcription of the three catecholamine-synthesizing enzymes in primary cultured bovine chromaffin cells by using the PKA-specific inhibitor N-[2-(p-bromocinnamylamine)ethyl]-5-isoquinolinesulfonamide (H-89). In the presence of 40 microM H-89, mRNA levels of TH, DBH, and PNMT were reduced to 17 +/- 8, 19 +/- 8, and 14 +/- 2% of the untreated control, respectively, in 24 h, and intracellular norepinephrine and epinephrine levels were decreased to 20 and 34%, respectively, in 72 h. At 20 microM, although the basal enzyme gene expression levels were little affected, their induction by forskolin was abolished and norepinephrine and epinephrine levels fell to 55 and 74%. This reduction in catecholamines at 20 microM was probably due to changes in the phosphorylation state of TH, as its enzymatic activity was found to be decreased to 66 and 69% in 48 and 72 h, respectively. Thus, PKA activity in bovine adrenal medullary cells coordinately regulates both basal and cyclic AMP-inducible gene expression of specific catecholamine-synthesizing enzymes, resulting in changes in intracellular catecholamine levels available for consequent neurohormonal activities.

Primary cultured chondrocytes of different origins respond differently to bFGF and TGF-beta

Responses of rib and ear chondrocytes to basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta) were investigated using high density primary culture isolated from the same rabbit. Degrees of tritiated thymidine, leucine, and proline incorporation were used as indicators of DNA, protein and collagen syntheses, respectively. 10 ng/ml bFGF increased thymidine, proline, and leucine incorporation into rib, but not ear, chondrocytes. 1 ng/ml TGF-beta enhanced thymidine incorporation into both chondrocytes but did not affect proline or leucine incorporation into the ear cells. When both growth factors were added simultaneously, both cells showed rises in syntheses of DNA, protein and collagen. Incorporation of [35S]sulfate, used as indicator of proteoglycan synthesis, was elevated by TGF-beta but was reduced by bFGF especially in the rib cells. This inhibitory effect of bFGF was not reversed by cotreatment with TGF-beta in both cell types. Thus, the origin and cellular differentiation states of chondrocytes seem to cause different responses to these growth factors.

Induction of gene expression of the catecholamine-synthesizing enzymes by insulin-like growth factor-I

The effects of insulin-like growth factor-I (IGF-I) on gene expression and the activities of the three enzymes specific for catecholamine biosynthesis, tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT), were determined in bovine adrenomedullary chromaffin cells primary cultured in serum-free medium. The mRNA level of TH was maximally elevated in the presence of IGF-I by 3.1 +/- 0.4-fold after 48 h, DBH by 5.1 +/- 0.3-fold in 24 h, and PNMT by 2.8 +/- 0.5-fold in 72 h. In addition, the activity of TH was increased by 77%, DBH by 70%, and PNMT by 23% in IGF-I-exposed cultures. In the absence of the growth factor, the mRNA levels of TH and DBH were decreased to 45 +/- 10% and 35 +/- 12% of the time-zero control within 48 h while PNMT mRNA was decreased to 82 +/- 5% only after 72 h. When the cells were cotreated with the protein tyrosine kinase inhibitor genistein, DBH induction by IGF-I was suppressed, confirming that the effect is mediated by tyrosine kinase. Cotreatment with the protein kinase A (PKA) inhibitor H89 caused complete reversal of the IGF-I-induced DBH increase and the effects of IGF-I treatment and PKA activation by forskolin were not additive, suggesting that PKA is involved in the signaling initiated by IGF-I in these cells.

Reduction of dopamine beta-hydroxylase gene expression by calcium in bovine chromaffin cells

We determined the effect of Ca++ influx on dopamine beta-hydroxylase (DBH) gene expression in primary cultured bovine chromaffin cells. The Ca++ ionophore A23187 (100nM) specifically reduced DBH mRNA to 15 +/- 10% of the untreated control while tyrosine hydroxylase was induced (142 +/- 15%) and phenylethanolamine N-methyltransferase was unchanged (107 +/- 11%). This effect on DBH was also observed with ionomycin, reversed by EGTA and unaffected by cycloheximide. Depolarization by potassium also resulted in DBH reduction which was reversed by the voltage dependent Ca++ channel blockers nifedipine and verapamil. DBH mRNA level reduced by A23187 could be re-induced by forskolin and DBH induced by forskolin could be reduced by the ionophore, suggesting that the cAMP and Ca++ pathways might act independently in regulating DBH gene expression.

Pharmacological characterization of PD 156707, an orally active ETA receptor antagonist

We describe the pharmacological characteristics of PD 156707 (sodium 2-benzo[1,3]dioxol-5-yl-4-(4-methoxy-phenyl)-4-oxo-3-(3,4,5- trimethoxy-benzyl)-but-2-enoate), a potent, orally active, nonpeptide antagonist of the endothelin A (ETA) receptor subtype. PD 156707 was designed on the basis of a compound identified by screening the Parke-Davis chemical library. PD 156707 is highly selective for the ETA receptor (ETAR) and inhibits the binding of [125I]-ET-1 to cloned human ETAR and ETBR with Ki values of 0.17 and 133.8 nM, respectively. PD 156707 antagonizes ET-1-stimulated phosphoinositide hydrolysis in Ltk- cells expressing cloned human ETAR with an IC50 value of 2.4 nM. PD 156707 inhibits vasoconstriction in isolated blood vessels mediated by ETAR (rabbit femoral artery) and ETBR (rabbit pulmonary artery) with pA2 values of 7.5 and 4.7, respectively. PD 156707 administered orally to rats blocked subsequent ETAR-mediated pressor responses in vivo but had no effect on ETBR-mediated dilator responses. As a potent and orally active ETA-selective antagonist, PD 156707 will be useful in defining the physiological and pathological roles of ETAR.

Pharmacological differences between rat and human endothelin B receptors

Cloned rat and human endothelin-B receptors (ETBR) were utilized to determine if there are significant pharmacological differences between highly homologous ETBR from different species. Recombinant rat and human ETBR were expressed in CHO-K1 cells, and radioligand binding studies were carried out with [125I]-ET-3 to determine the affinities of various ET receptor agonists and antagonists for rat and human ETBR. These receptors had similar affinities for a number of ETBR agonists (ET-1, ET-3, S6C, BQ 3020) and antagonists (Ro 47-0203, PD 142893). However, several peptide (PD 147452, PD 151583, BQ 788) and non-peptide (PD 156707, SB 209670) antagonists had different affinities for rat and human ETBR, with differences in Ki values between species ranging from 4.1- to 53.4-fold. The ETBR-selective agonist IRL 1620 also had a 5.7-fold higher affinity for rat ETBR than human ETBR. Thus despite their high degree of homology, rat and human ETBR show significant pharmacological differences with respect to both antagonist and agonist binding.

Differential induction of gene expression of catecholamine biosynthetic enzymes and preferential increase in norepinephrine by forskolin

We examined the effect of forskolin, an adenylate cyclase activator, on gene expression and the activities of the three enzymes specific for catecholamine biosynthesis [tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT)] and on the amounts of available catecholamines in primary cultured bovine adrenomedullary chromaffin cells. The results showed that TH was increased by 4.7 +/- 0.7-fold and 69% in mRNA and activity levels, respectively, compared with the untreated control. DBH was elevated by 3.2 +/- 0.2-fold in mRNA and 45% in activity. The increase in PNMT, on the other hand, was smaller: 1.7 +/- 0.2-fold in mRNA and 13% in activity. This relatively small increase in PNMT was reflected in the catecholamine levels in that the total epinephrine (EPI) was elevated by only 16% while norepinephrine (NE) was elevated by 99%, which caused a shift in the molar ratio of EPI to NE from 7.0 in the untreated control to 4.1 after forskolin treatment. A large portion of the elevated catecholamines was found in the medium, which represented a 10.1-fold increase for NE and a 6.4-fold increase for EPI compared with the control. Interestingly, this caused the remaining intracellular NE and EPI to be only 117 and 66% of the control, respectively. Thus, forskolin caused coordinate up-regulation of gene expression and enzyme activities of the three catecholamine-synthesizing enzymes but to different degrees, resulting in a relatively larger increase in NE than in EPI, both of which were released dramatically. This large enhancement of catecholamine release, as well as the dramatic shift in their ratio, implicates an important physiological role for cAMP in the regulation of in vivo sympathetic activities.

Intracellular induction pathways for CD23 antigen and surface immunoglobulins in human tonsillar B cells: the roles of protein kinase C and tyrosine kinase-mediated signals

The expression of CD23 on human tonsillar B cells is increased following treatment with interleukin 4 (IL-4) or 12-O-tetradecanoylphorbol 13-acetate (TPA), while that of surface immunoglobulins (sIgs) is increased by IL-4 but decreased by TPA. This suggests that the signaling by these effectors may result from distinct second messenger-generating systems. In this study, we attempted to elucidate the signal transduction pathways responsible for the expression of CD23 and sIgs by using different protein kinase C (PKC) and tyrosine kinase (TK) inhibitors. Our results showed that B cells expressed varying amounts of sIgs depending on different activators and inhibitors. Sphingosine, a PKC inhibitor, almost completely reversed the TPA-induced decrease in sIgM and sIgD expression. Other PKC inhibitors, e.g., H7 and staurosporine, had similar but less profound effects. In comparison, the up-regulation of CD23 by IL-4 and TPA was only partially blocked by these PKC inhibitors. TK inhibitors, such as herbimycin A and genistein, decreased both the IL-4- and TPA-induced CD23 expression by 50-80%, but had modest effects on sIgs expression. These findings indicate that CD23 and sIgs expression is regulated by independent pathways; PKC is important for the regulation of sIgs expression while the signals through TK pathways might play the major role in CD23 expression.

Effects of cAMP, glucocorticoids, and calcium on dopamine beta-hydroxylase gene expression in bovine chromaffin cells

To better understand the molecular mechanism underlying regulation of bovine dopamine beta-hydroxylase (DBH), the effects of elevated intracellular cAMP, glucocorticoids, and calcium were studied in primary cultured chromaffin cells. Elevation of intracellular cAMP by forskolin and treatment with its analog 8-bromo-cAMP caused an increase in the bovine DBH mRNA level by 3.5 +/- 0.5- and 7.8 +/- 0.9-fold, respectively, which was maximal at 6 h after the treatments. On the other hand, dexamethasone elicited no apparent change in DBH gene expression at various concentrations and time. The combined treatment with forskolin and dexamethasone resulted in the same degree of increase as that with forskolin alone. Increased intracellular calcium by the ionophore A23187 ranging from 50 to 500 nM caused DBH mRNA to decrease, which began to be observed after 6 h and was undetectable by 48 h. The results demonstrate the existence of coordinate and differential regulations among the enzymes involved in catecholamine biosynthesis in bovine adrenomedullary cells.

Interleukin 1 beta regulates glycogen metabolism in primary cultured rat hepatocytes

We examined the effects of human recombinant IL-1 beta on glycogen metabolism in cultured rat hepatocytes. When IL-1 beta was present at 8 nM in the culture medium for 15 hours prior to cell harvest, glycogen storage in hepatocytes was lowered approximately by 60% of the control. The enzymatic activity of glycogen synthase I in the IL-1 beta-treated cells (8 nM) was decreased by 70%; however, the activity ratio of the synthases I to D was not different from the untreated. In addition, the activity of glycogen phosphorylase a, the active form of phosphorylase involved in glycogenolysis, was increased by approximately 27% while the total phosphorylase activity was not changed. The data demonstrate for the first time that IL-1 beta lowers the intracellular glycogen contents in primary cultured rat hepatocytes.

Cloning, expression, and characterization of a gene encoding the human angiotensin II type 1A receptor

The human angiotensin II (AII) type 1a receptor gene and its upstream control sequence has been cloned from a human leukocyte genomic library. The promoter element CAAT and TATA sequences were found at -602 and -538, respectively, upstream from the translational initiation site. The deduced protein sequence is homologous to rat and bovine AT1a receptors (94.7% and 95.3% identity). The expressed gene exhibited high-affinity AII and Dup753 binding and was functionally coupled to inositol phosphate turnover. Northern analysis of human tissues showed AT1 receptor mRNA expression in placenta, lung, heart, liver, and kidney. Using 5' untranslated and coding sequence as probes in a Southern blot analysis, it was established that another AT1 subtype exists in the human genome.

Dopamine beta-hydroxylase: biochemistry and molecular biology

Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to norepinephrine (NE), and is known to exist in two forms: soluble and membrane-bound. It has been reported that the two forms are similar in their immunoreactivity, carbohydrate content, and binding affinities for various substrates, and are apparently dissimilar in subunit structures and hydrophilicity. Furthermore, added structural complexity is observed within sDBH itself. Our results indicate that purified sDBH, which runs a single band on a nondenaturing gel, exhibits three protein bands of 75 kDa, 72 kDa, and 69 kDa on SDS polyacrylamide gel. The majority of sDBH exists as a 72-kDa protein. The NH2-terminal amino acid sequence of this 72-kDa protein indicates that it consists of two polypeptides of equimolar concentrations, where one differs from the other by three extra amino acids at its NH2 terminus. Whether they are different proteolytic cleavage products is not known. Thus, the structure of DBH appears to be more complex than originally considered. In vitro translation of total mRNA of bovine adrenal medulla followed by immunoprecipitation of DBH produces a single 72-kDa band on SDS polyacrylamide gel. This suggests either that there is only one in vitro mRNA translation product, which is modified to become different forms of DBH, or that multiple translation products are present but are indistinguishable by molecular weight. These subjects have been discussed in detail in this paper.

Effects of dihydropyridines on tension and calcium-45 influx in isolated mesenteric resistance vessels from spontaneously hypertensive and normotensive rats

Contractile tension responses to norepinephrine and depolarizing potassium (80 mM K+), as well as calcium-45 influx stimulated by these agents, were studied in isolated mesenteric resistance vessels (each 100 microM internal diameter) from spontaneously hypertensive rats (SHRs) and from normotensive Wistar Kyoto rats (WKYs). Inhibitory effects of 2 dihydropyridine Ca++ antagonists, PN 200-110 (isradipine) and nisoldipine, on these parameters were also determined. Contractile responses to 80 mM K+ were inhibited by both Ca++ antagonists with the same potency and efficacy in SHR compared with WKY vessels (PN 200-110 IC50 = 2.8 +/- 1.3 X 10(-8) M in SHRs and 2.5 +/- 1.5 X 10(-8) M in WKYs; nisoldipine IC50 = 1.1 +/- 0.4 X 10(-8) M in SHRs and 1.2 +/- 0.9 X 10(-8) M in WKYs). However, contractile responses to norepinephrine (10(-4) M) were inhibited less potently by nisoldipine in SHR vessels (IC50 = 2.2 +/- 0.3 X 10(-9) M) compared with WKY vessels (IC50 = 1.6 +/- 0.6 X 10(-10) M). Similarly, PN 200-110 tended to be less (but not significantly less) potent in SHR vessels (IC50 = 3.3 +/- 1.8 X 10(-8) M) than in WKY vessels (IC50 = 3.4 +/- 0.9 X 10(-9) M); its efficacy was significantly depressed in the SHR vessels (by approximately 20%). When norepinephrine-stimulated calcium-45 influx was determined in the presence of these Ca++ antagonists, a similar profile emerged with respect to a comparison of SHR and WKY vessels. These results support a previously hypothesized alteration in receptor-activated Ca++ influx pathways in SHR mesenteric resistance vessels.

Different charge forms of aromatic-L-amino-acid decarboxylase

The isoelectric points (pI) of aromatic-L-amino-acid decarboxylase (AADC) from two species, rat and cow, were determined by chromatofocusing. The enzyme from both rat brain and adrenal has a pI of 5.5, while the bovine adrenal enzyme has a different pI of 5.0. Thus, the variation of isoelectric point for AADC is limited to species differences but not tissue differences.

Intracellular cysteine and glutathione delivery systems

Glutathione functions in catalysis, metabolism, transport, and reductive processes and in protection of cells by destruction of free radicals, reactive oxygen intermediates, and other toxic compounds of endogenous and exogenous origin. It also functions as a storage and transport form of cysteine. Depletion of glutathione (effectively accomplished by inhibition of its synthesis) increases sensitivity to radiation and to certain toxic compounds and is of value in combination with radiation therapy or chemotherapy in situations in which cell selectivity can be achieved. Increased cellular levels of glutathione protect cells against radiation and certain toxic compounds. Glutathione levels can be increased by administration of cysteine or of glutathione, but these approaches are not entirely satisfactory. Cellular glutathione levels can be increased by supplying substrate for gamma-glutamylcysteine synthetase or for glutathione synthetase. L-2-Oxothiazolidine-4-carboxylate is well transported into many cells and is converted by 5-oxoprolinase to cysteine, a substrate of gamma-glutamylcysteine synthetase. gamma-Glutamylcysteine and related compounds are effectively transported, especially into renal cells, thus providing substrate for glutathione synthetase; higher than normal levels of glutathione can be achieved because this enzyme is not significantly inhibited by glutathione, whereas gamma-glutamylcysteine synthetase is feedback-inhibited. Derivatives of glutathione that are effectively transported into cells (glutathione itself is not) offer another means of increasing glutathione levels. The monoethyl ester of glutathione (in which the glycine carboxyl group is esterified) is well transported in vivo into liver and kidney and into cultured fibroblasts and lymphoid cells. Glutathione levels much higher than usual can be obtained by this procedure, which protects lymphoid cells against the lethal effects of irradiation and mice against acetaminophen, and which therefore may be a relatively safe way to increase cellular resistance to radiation and certain toxic compounds.

Differences in norepinephrine activation and diltiazem inhibition of calcium channels in isolated rabbit aorta and mesenteric resistance vessels

The mechanisms of norepinephrine stimulation of calcium ion entry in isolated rabbit aorta and mesenteric resistance vessels were studied through measurements of effects on calcium-45 influx, tension, and membrane potential. The resistance vessels were considerably less sensitive to norepinephrine than the aorta. The aorta exhibited complex dose-response curves for norepinephrine-stimulated calcium influx and contraction, whereas these were simple in the arterioles. Both vessels were depolarized with increasing concentrations of potassium. Norepinephrine did not depolarize the aorta, whereas it did depolarize the mesenteric resistance vessels. This result supports the contention that norepinephrine opens receptor-operated channels to induce calcium entry in the aorta, while it may activate potential sensitive calcium channels in the mesenteric resistance vessels. However, the maximum depolarization with norepinephrine (10(-4) M) in the arterioles was completely blocked by 10(-5) M diltiazem, whereas that induced by 80 mM potassium was unaltered by the diltiazem. Furthermore, 10(-4) M norepinephrine was able to stimulate virtually the same contraction and calcium influx in 80 mM potassium-depolarized arterioles as in normal polarized tissues. These results are consistent with norepinephrine opening of receptor-operated channels to allow calcium entry in the rabbit mesenteric resistance vessels. That the behavior of norepinephrine-activated channels in the aorta is more complex than in the arterioles is further illustrated by a dramatically decreasing sensitivity of norepinephrine-stimulated calcium influx to diltiazem with increasing norepinephrine in the aorta but not in the arterioles.(ABSTRACT TRUNCATED AT 250 WORDS)

Bay K8644 differentiates between potential and receptor operated Ca2+ channels

Bay K8644 increased unidirectional Ca2+ influx and produced tension development in rabbit aorta. Both responses could be evoked in the tissue maximally stimulated with norepinephrine. When the arterial rings were maximally activated by high K+ depolarization, Bay K8644 was without effect. The tension evoked by high K+ and Bay K8644 was more sensitive to the dihydropyridine Ca2+ antagonist PY108-068 than norepinephrine induced tension. These results indicate that Bay K8644 activates only potential operated Ca2+ channels which are opened by high K+ depolarization.

Theoretical bases for vascular selectivity of Ca2+ antagonists

The purpose of these studies was to characterize mechanisms of activation of vascular tissues in order to clarify possible theoretical bases for Ca2+-antagonist (CAt) selectivity. Activation of rabbit aorta, mesenteric artery, and mesenteric resistance vessels by agonists and depolarizing potassium (K+) solution, and inhibition by CAts were studied by measurement of contractions, 45Ca fluxes, and membrane potentials (via intracellular electrodes). We found that the CAts studied (D-600, diltiazem, and nisoldipine) inhibited K+-induced Ca2+ influx and contractions in a closely correlated manner, suggesting inhibition of Ca2+ entry as their primary, if not sole, mechanism of action. Diltiazem and nisoldipine had no effect on intracellular Ca2+ release or on the contractile protein system. The following evidence was obtained to support the tenet that norepinephrine (NE) and 80 mM K+ open two distinct Ca2+ channels, one receptor-operated (ROC) and the other potential-operated (POC): (a) NE activated the rabbit aorta without eliciting a change in membrane potential; (b) NE activation of the rabbit mesenteric resistance vessels was accompanied by membrane depolarization, but this depolarization was blocked by 10(-5) M diltiazem, whereas that induced by 80 mM K+ was not; (c) 45Ca influx stimulated by 80 mM K+ and that stimulated by a maximal [NE] were additive when the two agents were administered together in the aorta and the resistance vessels; (d) the Ca2+-channel agonist Bay K8644 opens the POC but not the ROC in rabbit aorta, as it is capable of stimulating Ca2+ influx in addition to 10(-5) M NE, but not to 80 mM K+; (e) the CAts show selective inhibition of the POC over the ROC in the aorta, whereas diltiazem preferentially inhibits the ROC in the resistance vessels; and (f) alpha adrenoreceptor occupation, phosphodiesterase inhibition, or dibutyryl cyclic AMP selectively inhibits the POC over the ROC in the aorta.(ABSTRACT TRUNCATED AT 250 WORDS)

The mechanism of inhibitory action of diltiazem on vascular smooth muscle contractility

The mechanism of diltiazem-induced inhibition of smooth muscle contractility was investigated by studying its effects on tension development and Ca++ fluxes in the rabbit aorta. Diltiazem caused a dose-dependent inhibiton of contractions as well as Ca++ influx stimulated by alpha adrenoceptor activation and high-K+ depolarization. Diltiazem was roughly equally potent in inhibiting contractions induced by high-K+ and a low concentration of norepinephrine (NE; 10(-8) M). The contractions induced by high concentrations (10(-6)-10(-5) M) of NE were more resistant to diltiazem inhibition. It was also observed that there was a close relationship between diltiazem inhibition of Ca++ influx and inhibition of contraction when either 40 mM K+ or 10(-8) M NE was applied, but not when 10(-6) M NE was used. Also, diltiazem produced a noncompetitive inhibition of Ca++-induced contractions of depolarized rabbit aorta. Furthermore, there was a lack of parallelism between the smooth muscle effects of removal of [Ca++]ex and of addition of diltiazem. It is suggested that diltiazem causes inhibition of stimulated Ca++ influx by interacting with the Ca++ pathway involved in excitation rather than competing with Ca++ for the entry.

Evidence for two separated Ca2+ pathways in smooth muscle plasmalemma

The activation of rabbit aortic smooth muscle was studied by two most widely used vascular smooth muscle stimulants: alpha-adrenoceptor activation by norepinephrine (NE) and high-K+ depolarization. This was studied by measurements of isometric contractions and net as well as unidirectional Ca2+ fluxes. These parameters showed markedly differential sensitivities towards tow smooth muscle inhibitors used in this study: D600 and amrinone. By choosing an appropriate concentration of D600 or amrinone, Ca2+ uptake or Ca2+ influx induced by high K+ or NE could by selectively inhibited. Furthermore, by using unidirectional flux measurements it was demonstrated that Ca2+ influx stimulated by NE and high K+ were additive in nature. The data from the addivity experiment exclude the interpretation of a common Ca2+ pathway with two separate mechanisms for opening it. The data on three criteria employed in this study provide evidence for the existence of two independent Ca2+ pathways, one for each mode of activation, for Ca2+ influx known to be associated with these contractions.